[Elecraft] K3S - High SWR on 6 Meters

[Jim Brown]

On 6/13/2022 11:05 PM, N4ST - Jim wrote:
> SWR is fine with CW, problem only occurs with FT8.  Same antenna, same coax,
> same frequency.
> Only occurs on 6M.

I've seen guys trying to help asking questions for which I haven't seen 
answers. I'll try ONCE to help.

1. Describe the antenna. Where is it (with respect to the shack)?
2. As others have observed, the first thing to check in any system when 
something like this happens is to suspect EVERYTHING in the antenna 
system, ESPECIALLY ever piece of coax and every connection. That means 
getting serious to check that every connector is wrench tight, and to 
"rattle" all cables and connectors while watching for any changes.
3. What WAS the SWR on CW? What was it on FT8?
4. What happens if you click on TUNE in the software you're using for FT8?
5. What power did you use for each mode?
6. Are any of your coax connectors, including adapters, junk? If they 
don't say Amphenol 83-1SP, or have a MIL spec number stamped on them, 
there a VERY good chance that they are JUNK. When I got back on the air 
in 2003, I filled my parts stash with all sorts of no-name adapters from 
ham vendors. Over the next 6-8 years, they caused me all sorts of grief. 
Flimsy construction, spring wire in elbow adapters, out of physical 
tolerance center conductors that don't mate well to form a solid 
contact. I had Tee adapters fall apart.

73, Jim K9YC